Cannabis is the most widely-used illicit drug in the United States, and its use is currently most prevalent among adolescents and young adults. Cannabinoid receptors are densely distributed in the human brain and results from neuroimaging studies of abstinent cannabis users suggest functional brain abnormalities that are often not reflected on measures of neurocognitive functioning. In contrast, mounting evidence indicates that theory-driven measures of neurocognitive disinhibition are sensitive to the integrity of brain structures and circuits implicated in addiction pathophysiology and may be of value in the assessment of neurocognitive abnormalities in cannabis users. The proposed research plan will examine the role of neurocognitive disinhibition in cannabis use and addiction by characterizing performance on several measures of inhibitory control in a large sample (n = 216) of participants between the ages of 16 and 24 who will vary in exposure and use of cannabis, as well as prevalence of cannabis addiction. The investigation will be carried out in the context of a training plan that broadly includes new training in addictions neuroscience, conducting substance use research with adolescents, and longitudinal statistics and research methods. Training and mentorship will be provided by the candidate's sponsor (Dr Robin Mermelstein), co-sponsor (Dr Susan Tapert), and consultants (Drs Edwin Cook, Harriet de Wit, Donald Hedeker, Mitchell Roitman, and Ralph Tarter). In conjunction with the proposed training plan, the findings from this cross-sectional study will allow Dr Raul Gonzalez to lay the necessary groundwork and obtain essential new training for development of a longitudinal investigation to delineate the complex role of neurocognitive disinhibition in the development and maintenance of cannabis addiction, to be submitted as an R01 application during the final year of this award. The initial investigation will support the training aims by providing important "hands-on" training and by generating pilot data to develop a model and series of research studies that consider neurocognitive disinhibition in both the development and maintenance of cannabis addiction. The findings from the proposed study inform how neurocognitive disinhibition relates to use of cannabis and the severity of cannabis addiction. This will lead to future studies that may identify youth at risk for cannabis addiction and inform interventions.